SampleStatistic (Jetty :: Project 9.4.56.v20240826 API)

java.lang.Object
- org.eclipse.jetty.util.statistic.SampleStatistic

```
public class SampleStatistic
extends java.lang.Object
```
Statistics on a sampled value.

Provides max, total, mean, count, variance, and standard deviation of continuous sequence of samples.

Calculates estimates of mean, variance, and standard deviation characteristics of a sample using a non synchronized approximation of the on-line algorithm presented in Donald Knuth's Art of Computer Programming, Volume 2, Semi numerical Algorithms, 3rd edition, page 232, Boston: Addison-Wesley. That cites a 1962 paper by B.P. Welford: Note on a Method for Calculating Corrected Sums of Squares and Products

This algorithm is also described in Wikipedia in the section "Online algorithm": Algorithms for calculating variance.

Constructor Summary

Constructors
Constructor Description

SampleStatistic()

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`long`	`getCount()`
`long`	`getMax()`
`double`	`getMean()`
`double`	`getStdDev()`
`long`	`getTotal()`
`double`	`getVariance()`
`void`	`record(long sample)`	Records a sample value.
`void`	`reset()`	Resets the statistics.
`void`	`set(long sample)`	Deprecated. use `record(long)` instead
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - SampleStatistic
```
public SampleStatistic()
```
- Method Detail
  - reset
```
public void reset()
```
    Resets the statistics.
  - record
```
public void record(long sample)
```
    Records a sample value.
    
    Parameters:
    
    sample - the value to record.
  - set
```
@Deprecated
public void set(long sample)
```
    Deprecated.
    use record(long) instead
    
    Parameters:
    
    sample - the value to record.
  - getMax
```
public long getMax()
```
    Returns:
    
    the max value of the recorded samples
  - getTotal
```
public long getTotal()
```
    Returns:
    
    the sum of all the recorded samples
  - getCount
```
public long getCount()
```
    Returns:
    
    the number of samples recorded
  - getMean
```
public double getMean()
```
    Returns:
    
    the average value of the samples recorded, or zero if there are no samples
  - getVariance
```
public double getVariance()
```
    Returns:
    
    the variance of the samples recorded, or zero if there are less than 2 samples
  - getStdDev
```
public double getStdDev()
```
    Returns:
    
    the standard deviation of the samples recorded
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object